What's Under the Plastic Sheath on a '60-62 Tach Cable?

[Bob B.]

Hi all,

I have a early (1959) NOS service replacement tach cable for a 1957 Corvette, but the black plastic over the metal sheath isn't correct for 1957. I'm assuming that it is the regular metal sheath for 1957 beneath the plastic and I'd like to remove it, but I wanted to see if anyone has one that they have done this on or if they have one that the plastic is cracked or gone enough to see what is underneath.

Thanks,

Bob